Configurable safety light receptacle

ABSTRACT

An electrical receptacle provide outlets and a cavity for receiving an insert. The insert connects to the electrical main through the receptacle and can provide additional functionality through the insert including emergency lighting, night lighting, gas detectors and charging connections.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 13/908,397 filed on Jun. 3, 2013, which is acontinuation-in-part application of and claims priority to U.S. patentapplication Ser. No. 11/848,615 filed Aug. 31, 2007, which claimspriority to and the benefit of U.S. Provisional Application No.60/847,185 filed Sep. 26, 2006, the entire contents of each beingincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to electrical wall receptacles. Inparticular, this invention relates to replacement wall receptacles thatcan house specific function inserts having common mechanical andelectrical interfaces

BACKGROUND OF THE INVENTION

In most conventional buildings, both residential and commercial,electrical receptacles are spaced out on walls at fixed intervals. Thisallows for convenient distribution of power, but does not typicallyprovide any additional functionality. Each receptacle typically providestwo outlets. The style of the provided outlet is usually determined bygeographical location and the electrical standards of region.

In many buildings, emergency lighting is required to provide a means fornavigating in the dark. There are two common needs for navigation in thedark. The first is a conventional night light situation, whereby a lightis required to provide illumination in a dark environment on a regularbasis; the other is for backup lighting. Backup lighting is alsoreferred to as blackout lighting, and is required when there is a lowerfailure and lighting cannot be turned on.

The prior art has attempted to address this situation by developing anumber of solutions including both nightlights and rechargeable lights.Nightlights are typically plugged-in to one of the outlets provided in astandard receptacle. They often include switches, that can be eitherphotosensitive or manually controlled. This allows the nightlight to bedeactivated during daylight when it is not needed. Rechargeable lightsare also designed to be connected to an outlet. Many of these lightswill activate when they are no longer in a charging state. Thus, arechargeable flashlight of this design will activate both upon beingunplugged and upon a power failure.

One problem with both of these designs is that they consume anelectrical outlet, and require external components that can be removedand accidentally disconnected. Thus, an integrated solution providesadvantages.

Backup lighting is necessary to ensure that individuals can safelynavigate through dark and even unfamiliar locations. The need for theselights to operate on emergency power is increased in locations such ashospitals, nursing homes, and both industrial and commercial buildingsin which individuals may be unfamiliar with floor plans and layouts.Residential homes benefit from emergency lighting as it enableshomeowners, residents, and guests to safely navigate the home when poweroutages occur. Emergency rescue personnel are often hampered by the lackof knowledge of floor designs, increasing the time and effort requiredto rescue people from potentially dangerous situations.

Many solutions to backup lighting involve a dedicated lighting unitconnected to the electrical power main. When a loss of power isdetected, these systems turn on. Although they provide blackoutlighting, they require additional wiring, which is inconvenient duringconstruction, and expensive as a retrofit. The external units are oftenunsightly and are single purpose infrastructure items that serve nofunction other than emergency lighting.

A key limitation of conventional emergency lighting, especiallyconsidering residential utilization, is installation of bulky andgenerally unappealing systems that require direct access to electricaloutlet. In addition, these conventional emergency lights have a singleoperational function and hence cannot be tailored different emergencylighting scenerios (ie power loss, low-light illumination, smoke/firedetection). In addition, alternate lighting can be provided by externaldevices (ie a night light plugged into a receptacle) however, these tendto be bulky and diminish the use of the wall receptacle for otherpurposes.

Thus, there remains a need for discrete emergency lighting that canautomatically illuminate and can allow a user enough flexibility toselect the appropriate emergency illumination situation.

Prior art attempts at addressing this need are discussed below.Typically they do not provide a sufficiently integrated and flexiblesystem.

U.S. Pat. Nos. 6,010,288 and 6,000,807 both describes a light switchplate and wall receptacle plate that are installed in place of thenormal flush mounted plastic cover plates. While generally easy toinstall as this senses the absence of power wirelessly, this type offixture plate (in both thickness and length) is bulky, potentiallyunappealing and only has the power outage lighting feature via LEDlights. Similarly U.S. Pat. No. 5,473,517 also use this same type ofbulky light switch plate but utilizes direct connection to 120 VAC tosense the presence or absence of power to both with the illuminationsource being a relatively inefficient fluorescent tube arrangement.

U.S. Pat. No. 6,045,232 describe an emergency light arrangement that hasboth the capability of providing lighting for power out conditions andnight light for illumination during low light levels. While this doeshave expanded utility as it provides more than just one type ofemergency lighting and does not utilize bulky plates, this is a directreplacement of the wall receptacle removing the ability to use this as anormal outlet. This then precludes the use of this in certain locationswhere there are limited numbers of wall receptacles.

U.S. Pat. No. 6,805,469 describes the complete replacement of theinternal wall receptacle and light switch units with a custom lightswitch and wall receptacle that internally contain the electronics andbatteries for an emergency light. Both arrangements use illumination(light switch via the toggle, wall receptacle via the face of thereceptacle body) during power out conditions and conform to the size andshape of normal light and wall receptacles, thus maintaining the normalappearance. However, both have only one possible function andimportantly, when the batteries require replacement or the device hasfailed and requires replacement, the user must disassembly the unit fromthe electrical box creating a potential safety hazard for the user.

Thus there remains a need for an emergency lighting system that conformsto the normal configuration these standard wall receptacles, contain alevel of flexibility to allow the user to select the desired functions,maintain the full use and capability of the substituted wall receptacle,and is easy and safe for the user. In addition, as technology changesand advances, there also is a need to ensure that the state-of-the-artcan be utilized with minimal user cost or change to the installedsystem.

SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at leastone disadvantage of the prior art.

In a first aspect of the present invention, there is provided anelectrical receptacle for mounting in a wall or receptacle box, thereceptacle having an externally accessible face. The receptaclecomprises an electrical main connection point, an electrical out, acavity and a demountable or removable insert. The electrical mainconnection point connects the receptacle to the electrical main. Theelectrical outlet is connected to the electrical main connection pointand is set into the externally accessible face. The outlet has astandard interface for connecting external loads to the electrical main.The cavity is set into the externally accessible face of the electricaloutlet, and has a connection to the electrical main connection point.The cavity receives inserts and connects them to the electrical main.The demountable insert is sized for insertion in to the cavity, andreceives power from the electrical main through the connection to theelectrical main connection point.

In embodiments of the first aspect of the present invention, the cavityand the insert include cooperating latches for releasably locking theinsert into the cavity. In other embodiments, the insert includes abattery-powered light activated when power from the electrical main isnot present. Optionally, the insert includes a battery charger forcharging the battery connected to the battery powered light when powerfrom the electrical main is present. In further embodiments, the insertincludes a light activated by a photosensor. In other embodiments, theinsert includes a current converter, such as a transformer, and asocket. The current converter receives power from the electrical mainand converts the power to a direct-current signal. The socket, which maybe a universal serial bus socket, is connected to the current converterand provides external access to the direct current signal. In otherembodiments, the insert can include either a wireless network bridge ora powerline networking bridge connected to an externally accessiblenetwork jack. The insert can also provide a further outlet, eitherdirectly on the face of the receptacle on through an extension cord.

In a second aspect of the present invention, there is provided anelectrical receptacle for mounting in a wall or receptacle box, thereceptacle having an externally accessible face. The receptaclecomprises an electrical main connection point, an electrical outlet anda cavity. The electrical main connection point connects the receptacleto the electrical main. The electrical outlet is connected to theelectrical main connection point and is set into the externallyaccessible face. The outlet has a standard interface for connectingexternal loads to the electrical main. The cavity is set into theexternally accessible face of the electrical outlet, and has aconnection to the electrical main connection point. The cavity is sizedfor receiving inserts and connects the inserts to the electrical main.

In embodiments of the second aspect of the present invention, thereceptacle includes a second electrical outlet set into the externallyaccessible face. The cavity can be centrally located between the twoelectrical outlets on the externally accessible face. The cavity caninclude a latch for interacting with a cooperative element on an insertto prevent accidental removal of an inserted insert. The cavity caninclude a connection point not connected to the electrical mainconnection point, such as a computer network connection point. Theconnection point can alternatively be used to provide an interface forcontrolling the connection of the electrical outlet to the electricalmain.

In a third aspect of the present invention, there is provided an insert,for insertion into a cavity in the face an electrical receptacle. Theinsert comprises electrical contacts and a substrate. The electricalcontacts connect to the receptacle and draw electrical power from anelectrical main connected to the receptacle. The substrate supports theelectrical contacts.

In embodiments of the thirds aspect of the present invention, there isprovided a latch, connected to the substrate, for mating with arespective latching system in the cavity to prevent accidental removalof the insert.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the attached Figures, wherein:

FIG. 1 illustrates the assembled wall receptacle and insert according toan embodiment of the present invention;

FIG. 2 shows the insert of FIG. 1 removed from the interface cavity inthe wall receptacle;

FIG. 3 is a representation of an exemplary layout of components on theinsert;

FIG. 4 shows a wall receptacle according to an embodiment of the presentinvention with the insert removed;

FIG. 5 illustrates the floor illumination of an embodiment of thepresent invention;

FIG. 6 is an illustrative circuit diagram for use in an embodiment of apower out lighting insert;

FIG. 7 is an exemplary diode-based power out illumination insert circuitdesign; and

FIG. 8 is an exemplary night light insert circuit design.

DETAILED DESCRIPTION

The present invention is directed to a configurable receptacle, whichcan be configured with a variety of function specific inserts such assafety lights and motion detectors.

Reference is made below to specific elements, numbered in accordancewith the attached figures. The discussion below should be taken to beexemplary in nature, and not as limiting of the scope of the presentinvention. The scope of the present invention is defined in the claims,and should not be considered as limited by the implementation detailsdescribed below, which as one skilled in the art will appreciate, can bemodified by replacing elements with equivalent functional elements.

Systems of the present invention provide a mechanism for making use ofstandard building wiring to provide additional functionality includingemergency lighting. In one embodiment of the present invention, amodification to the design of an electrical receptacle is provided. Thisredesign allows for an insert to be placed into a cavity in thereceptacle body. A standard electrical receptacle provides two outlets.When installed in a receptacle box, the receptacle is typically coveredby a faceplate. It is preferable for the receptacle of the presentinvention to function with standard receptacle boxes, and in somedesigns faceplates.

As illustrated in FIG. 1, receptacle body 100 has been modified toaccept insert 200. The receptacle body 100 provides two outlets in whatis referred to as a decora-style configuration. In this configuration,the outlets are vertically spaced from each other, and a faceplateserves to surround the central structure that houses the outlets. Insuch a configuration, insert 200 is placed into a cavity between the twooutlets. A decora-style faceplate can be attached to the receptaclewithout any modification. This allows for compatibility with a largenumber of existing elements, and allows for easy retrofitting. Abuilding can be retrofit to these receptacles with no tools other than astandard screwdriver.

FIG. 2 provides an exploded view of the receptacle 100 and insert 200.Insert 200 is inserted into cavity 110 in receptacle 100. As notedabove, receptacle 100 can be accommodated into a standard decora-stylefaceplate. Insert 200 provides a physical an electrical interface forvarious insert configurations, each of which can provide alternatefunctionality. In the illustrated embodiment, insert 200 providesillumination, although alternate inserts can provide other functionssuch as chargers for different connection, additional outlet, smokedetectors, and other functions that will be apparent to those skilled inthe art. Insert 200 includes a printed circuit board 210 that houses thecontrol circuitry and elements for the intended functionality. Faceplate220 provides a cover that preferably matches with surface of thereceptacle. On the faceplate is provided a light 230, preferably a lightemitting diode (LED), and a test switch 240 which can be used todetermine if the insert is functional.

As shown in FIG. 3, PCB 210 includes contacts 211 that are connected tothe electrical main that the outlets of the receptacle are connected to.This provides PCB 210, and any circuitry thereupon, with power. Asillustrated in FIG. 3, embodiments of the present invention can providea battery 212 on the PCB 210. Battery 212 is used to provide LED 230with power during blackout situations. Contacts 211 provide a mechanismfor connection to the 120 VAC once the insert 200 is fully inserted inthe receptacle body 100. Although reference is made herein to 120 VAC asa source, it will be understood that other power standards can be usedwith suitable modifications to electrical designs on the inserts. Theassembled insert 200 is held into the receptacle body 100 by mountingmechanisms such as plastic latches 221 on the insert cover plate 220.These latches provide the necessary protection from accidental removaland child protection as the removal of this embodiment of the presentinvention requires a small screwdriver or specialized tool on both theleft and right side of the insert cover plate 220 to unlock the latches221 for removal. Note that dependent on the insert function, all or aportion of these elements may be present.

As shown in FIG. 4, the receptacle body 100 provides the insert cavity110 and the nominal wall receptacle interfaces for normal 120 VAC powervia the receptacle plugs 102 and installation screw terminals 101.

For illumination-based inserts, a high intensity LED 230 provides floorillumination 300 as indicated in FIG. 5. Although this does may notprovide the same degree of illumination as a dedicated emergencyblackout light, a large number of distributed lights can be employed.This provides a distributed lighting in a room as opposed to a largecentralized point source of light. If light 230 makes use of LEDs, asillustrated in the embodiments, the power-on time provided by thebattery can exceed the time provided by a conventional battery backuplight that makes use of halogen or standard incandescent lighting.

Below, exemplary designs for functional inserts are provided. Oneskilled in the art will appreciate that alternate designs are possible,as are designs for functions not described herein.

FIG. 6 illustrates a relay-based schematic for illumination during powerout conditions. In operation, the design presented obtains a low powerrectified signal from the 120 VAC main voltage. Note that for 220-240AC, C2 is decreased in half. Connection to the receptacle is provided bycontacts AC1 and AC2. The rectified voltage powers a relay such that theNO contact is engaged which disconnects the battery from the LED. Whenpower is removed (i.e. a power black-out) the relay triggers the NCcontact and the LED illuminates for as long as power is off or until thebattery is drained (>60 hours). At any time, the LED and battery can betested via an external push button. Higher illumination intensity can beachieved by reducing R1—note this would reduce the total illuminationtime. In an alternate embodiment, a rechargeable battery can be used andcan be charged during non-blackout periods.

FIG. 7 illustrates an exemplary diode biased based schematic forillumination during power out conditions. While performing the sameemergency lighting function, the relay has been removed and a passivevoltage difference is used to enable or disable the LED light. Inoperation, a low power rectified signal is obtained from the 120 VACmain voltage. Note that for 220-240 AC, C2 is decreased in half. Thisrectified voltage generates a potential between R3 and R1 that is higherthan the battery voltage (3V). This creates a reverse bias state indiodes D3 and D1. In this reverse bias state, current cannot flow fromthe battery to the LED. When power is removed (i.e. power black-out) thehigher voltage potential is removed, power can flow from the battery,and the LED illuminates for as long as power is off or until the batteryis drained (>60 hours). At any time, the LED and battery can be testedvia an external push button. Higher illumination intensity can beachieved by reducing R1—note this would reduce the total illuminationtime.

FIG. 8 illustrates a Night Light insert. In operation, the designpresented obtains a low power rectified signal from the 120 VAC mainvoltage. Note that for 220-240 AC, C2 is decreased in half. The 6.3Vrectified voltage is used to power the circuit and drive the LED's. TheR1/R3 voltage divider generates a input to the Voltage Comparator. Thephotoconductive cell has an impedance of 1M in the dark and 45K in thelight. Internal to the voltage comparator is a 1.24 Vref, so during theday (i.e. lighted conditions) the input voltage to the comparator wouldbe between 3.0 and 2.0V. Once the light is sufficiently reduced, theimpedance of R1 is decreased, the voltage input drops below 1.24V theLED's illuminate. One skilled in the art will appreciate that thephotoconductive cell act as a photosensor to determine ambient lightlevels. When a threshold is crossed, the photosensor activates ordeactivates the light as required. Numerous other implementations willbe understood by those skilled in the art.

Other, non-illustrated inserts are contemplated. As the insert providesa mechanism for drawing power from the 120 VAC main, a number ofdifferent inserts can be provided. Rechargeable devices, such ascellular phones, can provide inserts that allow charging withoutoccupying an outlet. Many devices now draw power for charging from astandard Universal Serial Bus (USB) connection. Typically a Type Aconnector to a computer or to a power converter is used to connect to adevice. A current converter insert that transforms the AC current to aDC current and provides a USB connection can be provided to allow forcharging devices such as cellular phones, cameras, portable musicplayers and other electronic devices. The current converter beimplemented using any of a number of standard devices includingtransformers, rectifiers and other devices that will be well known tothose skilled in the art.

Computer network connections can be provided in inserts. Additionalcontacts can be provided so that computer networking cabling can beconnected to the receptacle and accessed through the insert.Alternatively, power-line networking connections can be provided usingindustry standard interfaces. Such a design provides networkconnectivity to any location that a computer would need to be plugged into an outlet. In an alternate embodiment, a network jack can beprovided. To connect to a network, a wireless transceiver can beemployed, and powered from the contacts connecting to the electricalmain. The wireless connection can be any of a number of standardconnections, such as any of the IEEE802.11 family of standards, or evenusing a wide area networking standard such as WiMax. Alternatively, aproprietary networking standard can be provided.

Although reference has been shown to providing only two contacts, inview of the above discussion multiple contacts can be provided for anynumber of reasons. One skilled in the art will appreciate that a thirdcontact to the electrical main can be provided to offer groundedconnections. This allows the insert to connect to a cable that providesfurther outlets. Thus, a receptacle can provide standard outlets, andthrough the use of the insert can provide further outlets.

In an alternate embodiment, the receptacle provides a single outlet, andprovides at least one insert connection point. Thus, in the shape of aconventional outlet, and allowing compatibility with a standardreceptacle, a single outlet can be provided with multiple inserts.

Further insert designs for motion detectors, security system sensors,smoke detectors, radon detectors, noxious gas detectors such as carbondioxide detectors, carbon monoxide detectors and natural gas detectors,have been contemplated and can be implemented by those skilled in theart by placing standard designs for these system on an insert anddrawing electrical power from the power main.

The additional contacts can be employed for any number of uses. In oneembodiment, the extra connectors allow a timer insert to control theavailability of the outlets in accordance with a predefined schedule. Areceptacle can make use of logic circuitry to identify the insert usinga set of contacts, and then handle the signals from the contactsappropriately. This allows a single set of contacts to be used for bothoutlet control, such as with a timer insert, and for other purposes suchas networking, or other communications activities.

One skilled in the art will appreciate that the present inventionprovides not only for designs of inserts, but also for receptacles thataccept such inserts. By providing power to an insert in a receptacle, avariety of components can be distributed through a commercial orresidential environment. Because they do not require external access toa power supply, they provide a simpler and more pleasing installation.Thus, motion detectors can be installed and powered off the connection,and can be connected to security systems. Because installation of thesereceptacles can be done during construction, or as a retrofit, dataconnections to systems such as security systems can be provided usingeither a wired or wireless connection. Power line communication can alsobe employed.

Inserts can be provided with processors and communications interfaces sothat a set of co-located inserts can communicate and providefunctionality based on conditions at a number of different inserts.

The above-described embodiments of the present invention are intended tobe examples only. Alterations, modifications and variations may beeffected to the particular embodiments by those of skill in the artwithout departing from the scope of the invention, which is definedsolely by the claims appended hereto.

What is claimed is:
 1. A device for use in conjunction with aconventional electrical utility work box and a faceplate comprising: ahousing to fit within an electrical utility work box comprising at leasta front face, the housing comprising; a first mounting means to affixthe housing to the electrical utility work box; a second mounting meansto affix the faceplate to the housing; a plurality of electricalinterfaces, each electrical interface allowing connection to apredetermined electrical signal forming part of an electrical utilitysupply; an electrical outlet disposed within the front face of thehousing forming a permanent part of the housing, the electrical outletpermanently connected to the plurality of electrical interfaces andallowing external loads to be connected to the electrical utility supplywhen the housing is connected to the electrical utility supply with thefaceplate attached, the electrical outlet accessible through a firstopening in the faceplate; and a cavity disposed within the front face ofthe housing allowing the insertion and removal of a demountable insertinto and from the front face of the housing when the housing is mountedwithin the electrical utility work box with the faceplate attached andcomprising a first part of a retention means to retain the demountableinsert when inserted into the cavity, the cavity accessible through asecond opening in the faceplate and comprising a plurality of firstcontacts, each first contact electrically coupled to a predeterminedelectrical interface of the housing, wherein the demountable insert issized for insertion into the cavity within the front face of the housingand providing a function independent of the electrical outlet, thedemountable insert capable of insertion and removal when the faceplateis attached to the housing, the demountable insert comprising a secondpart of the retention means to retain the demountable insert wheninserted into the cavity.
 2. The device according to claim 1 wherein,the demountable insert further comprises a control circuit, the controlcircuit coupled to a predetermined functional subset of elements, theelements comprising an optical emitter, an optical sensor, a chemicalsensor, a biological sensor, a motion sensor, a rechargeable battery, agas detector, a microphone, and a loudspeaker.
 3. The device accordingto claim 1 wherein, the housing comprises a second electrical outletdisposed within the front face of the housing forming a permanent partof the housing, the second electrical outlet permanently connected tothe plurality of electrical interfaces and allowing external loads to beconnected to the electrical utility supply when the housing is connectedto the electrical utility supply with the faceplate attached, the secondelectrical outlet accessible through a third opening in the faceplate.4. The device according to claim 1 wherein, the housing furthercomprises a second cavity disposed within the front face of the housingallowing the insertion and removal of another demountable insert whenthe housing is mounted within the electrical utility work box with thefaceplate attached and comprising the first part of the retention meansto retain the other demountable insert when inserted into the secondcavity, the second cavity accessible through a fourth opening in thefaceplate and comprising a plurality of third contacts, each thirdcontact electrically coupled to a predetermined electrical interface ofthe housing.
 5. A device for use in conjunction with a conventionalelectrical utility work box and a faceplate comprising: a front face,being the outer face of the device presented to a user when the deviceis mounted into the electrical utility work box; a first mounting meansto affix the device to the electrical utility work box; a secondmounting means to affix the faceplate to the device; a plurality ofelectrical interfaces, each electrical interface allowing connection toa predetermined electrical signal forming part of an electrical utilitysupply; an electrical outlet disposed within the front face of thedevice forming a permanent part of the device, the electrical outletpermanently connected to the plurality of electrical interfaces andallowing external loads to be connected to the electrical utility supplywhen the device is connected to the electrical utility supply with thefaceplate attached, the electrical outlet accessible through a firstopening in the faceplate; and a cavity disposed within the front face ofthe device allowing the insertion and removal of a demountable insertinto and from the front face when the device is mounted within theelectrical utility work box with the faceplate attached and comprising afirst part of a retention means to retain the demountable insert wheninserted into the cavity, the cavity accessible through a second openingin the faceplate and comprising a plurality of first contacts, eachfirst contact electrically coupled to a predetermined electricalinterface of the device.
 6. The device according to claim 5 wherein; thedemountable insert comprises a second part of the retention means toretain the demountable insert when inserted into the cavity; and theretention means exploits cooperating latches for releasably retainingthe demountable insert into the cavity.
 7. The device according to claim5 wherein, the device comprises a second electrical outlet disposedwithin the front face of the device forming a permanent part of thedevice, the second electrical outlet permanently connected to theplurality of electrical interfaces and allowing external loads to beconnected to the electrical utility supply when the device is connectedto the electrical utility supply with the faceplate attached, the secondelectrical outlet accessible through a third opening in the faceplate.8. The device according to claim 5 further comprising, a second cavitydisposed within the front face of the device allows for the insertionand removal of another demountable insert when the device is mountedwithin the electrical utility work box with the faceplate attached andcomprising a first part of a retention means to retain anotherdemountable insert when inserted into the second cavity, the secondcavity accessible through a fourth opening in the faceplate andcomprising a plurality of third contacts, each third contactelectrically coupled to a predetermined electrical interface of thedevice.
 9. A device for use in conjunction with a conventionalelectrical utility work box, a housing for mounting to the conventionalelectrical utility box and a faceplate for mounting to the housingcomprising: a demountable insert sized for insertion into a cavitywithin a front face of the housing facing a user when mounted to theelectrical utility box and providing a function independent of anelectrical outlet within the housing, the demountable insert capable ofinsertion and removal from the front face of the housing through anopening within the faceplate when the faceplate is attached to thehousing and the housing is mounted within the electrical utility workbox, the cavity within the housing also comprising a first part of aretention means and the demountable insert comprising a second part ofthe retention means to retain the demountable insert when inserted intothe cavity within the front face of the housing.
 10. The deviceaccording to claim 9 wherein, the demountable insert further comprises aplurality of second contacts, each second contact providing electricalconnection to a predetermined first contact of a plurality of firstcontacts disposed within the cavity within the housing when thedemountable insert is inserted into the cavity within the housing,wherein each first contact electrically coupled to a predeterminedelectrical interface within the housing that supports connection to apredetermined electrical signal forming part of an electrical utilitysupply.
 11. The device according to claim 9 wherein, the demountableinsert includes power converter for converting the electrical utilitysupply to a predetermined direct-current electrical signal; and thedemountable insert includes an electrical interface according to apredetermined standard allowing external electrical loads to beconnected to the electrical interface whilst the demountable insert isinserted into the housing with the faceplate attached.
 12. The deviceaccording to claim 9 wherein, the demountable insert further comprises acontrol circuit, the control circuit coupled to a predeterminedfunctional subset of elements, the elements comprising an opticalemitter, an optical sensor, a chemical sensor, a biological sensor, amotion sensor, a rechargeable battery, a gas detector, a microphone, anda loudspeaker.
 13. The device according to claim 9 wherein, thedemountable insert comprises an electrical mains interface allowingexternal loads to be connected to the electrical utility supply, theelectrical mains interface at least one of according to a standard otherthan that of the electrical utility supply and an externally accessiblesocket of the insert connected to the insert by an electrical cable.